Photographic processes and products using 4,8-diamino substituted 1,5-naphthoquinone dye developers

ABSTRACT

NOVEL NAPHTHOQUINONE DYE DEVELOPERS (NAPHTHOQUINONE DYES WHICH ARE ALSO SILVER HALIDE DEVELOPING AGENTS) AND TO PHOTOGRAPHIC SYSTEMS EMPLOYING THE SAME.

United States Patent fOlfice PHOTOGRAPHIC PROCESSES AND PRODUCTS USING 4,8-DIAMINO SUBSTITUTED 1,5-NAPH- THOQUINONE DYE DEVELOPERS Stanley M. Bloom, Waban, Mass., assignor to Polaroid Corporation, Cambridge, Mass. No Drawing. Filed Oct. 27, 1967, Ser. No. 678,547 Int. Cl. G03c 5/30 US. Cl. 96--66 11 Claims ABSTRACT OF THE DISCLOSURE Novel naphthoquinone dye developers (naphthoquinone dyes which are also silver halide developing agents) and to photographic systems employing the same.

It is one object of the present invention to provide novel processes, products and compositions for the development of silver halide emulsions, in which novel colored silver halide developing agents are used to develop a latent photographic image.

Another object is to provide novel systems for the development of silver halide emulsions, in which colored developing agents develop a photographic latent image and impart a reversed or positive colored image of said latent image to a superposed imagereceiving element.

A further object of this invention is to provide a novel class of compounds useful in photographic products, processes and compositions such as described and claimed in US. Pat. No. 2,983,606, issued to Howard G. Rogers.

A further object is to provide novel products and processes suitable for use in preparing monochromatic and multichromatic photographic images.

Another object is to provide a novel class of naphtohoquinone dyes which are also silver halide developing agents.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the processes involving the several steps and the relation and order of one or more of such steps with respect to each of the others and the products possessing the features, properties and the relation of components which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

US. Pat. No. 2,983,606, issued May 9, 1961 to Howard G. Rogers, discloses difiusion transfer processes wherein a photographic negative material, such as a photographic element comprising an exposed silver halide emulsion, is developed in the presence of a dye developer to impart to an image-receiving layer a reversed or positive dye image of the developed image by permeating into said emulsion layer a suitable liquid processing composition and bringing said emulsion layer into superposed relationship with an appropriate image-receiving layer.

It is an object of this invention to provide additional dye developers suitable for use in such processes.

In carrying out the process of this invention, a photosensitive element containing a silver halide emulsion is exposed and wetted with a liquid processing composition, for example, by immersing, coating, spraying, flowing, etc., in the dark, and the photosensitive element super- .posed, prior to, during or after wetting, on an imagereceiving element. In a preferred embodiment, the photosensitive element contains a layer of dye developer, and the liquid processing composition is applied to the photosensitive element in a uniform layer as the photosensitive element is brought into superposed position with an image-receiving element. The liquid processing composi- I 3,666,469 Patented May 30, 1972 tion permeates the emulsion to provide a solution of dye developer substantially uniformly distributed therein. As the exposed silver halide emulsion is developed, the oxidation product of the dye developer is immobilized or precipitated in situ with the developed silver, thereby providing an imagewise distribution of unoxidized dye developer dissolved in the liquid processing composition. This immobilization is apparently, at least in part, due to a change in the solubility characteristics of the dye developer upon oxidation, and especially as regards its solubiltiy in alkaline solutions. It also may be due, in part, to a tanning effect on the emulsion by the oxidized developing agent. At least part of this imagewise distribution of unoxidized dye developer is transferred, by irnbibition, to a superposed image-receiving layer. Under certain circumstances, the layer of the liquid processing composition may be utilized as the image-receiving layer. The image-receiving layer receives a depthwise diffusion, from the emulsion, of unoxidized dye developer, without appreciably disturbing the imagewise distribution thereof, to provide a reversed or positive, colored image of the developed image. The image-receiving element may contain agents adapted to mordant or otherwise fix the diffused, unoxidized dye developer. If the color of the diffused dye developer is affeoted by changes in the pH of the image-receiving element, this pH may be adjusted in accordance with well-known techniques to provide a pH afi'ording the desired color. Imbi'bition periods of approximately one minute have been found to give good results, but this contact period may be adjusted where necessary to compensate for variations in temperature or other conditions. The desired positive image is revealed by stripping the image-receiving element from the photosensitive element at the end of the irnbibition period.

The dye developers of this invention may be utilized in the photosensitive element, for example in, on or behind the silver halide emulsion, or they may be utilized in the image-receiving element or in the liquid processing composition. In a preferred embodiment, a coating or layer of the dye developer is placed behind the silver halide emulsion, i.e., on the side of the emulsion adapted to be located most distant from the photographed subject when the emulsion is exposed and preferably also adapted to be most distant from the image-receiving element when in superposed relationship therewith. In this preferred embodiment, the layer of dye developer may be applied by using a coating solution containing about 0.5 to 8% by weight of the dye developer. Similar concentrations may be used if the dye developer is utilized as a component of the liquid processing composition. In an especially useful mode of dispersing the dye developers in the photosensitive elements, the dye developer is dissolved in a water-immiscible solvent and then dispersed in a gelatin coating solution.

The liquid processing composition above referred to comprises at least an aqueous solution of an alkaline compound, for example, diethylamine, sodium hydroxide or sodium carbonate, and it may contain the dye developer. In some instances, it may contain a minor amount of a conventional developing agent. If the liquid processing composition is to be applied to the emulsion by being spread thereon, preferably in a relatively thin, uniform layer, it may also include a viscosity-increasing compound constituting the film-forming material of the type which, when said composition is spread and dried, Will form a relatively firm and relatively stable film. A preferred film-forming material is a high molecular weight polymer such as a polymeric, water-soluble ether inert to an alkali solution, as, for example, a hydroxyethyl cellulose or sodium carboxymethyl cellulose. Other filmforming materials or thickening agents whose ability to increase viscosity is substantially unaffected when left in solution for a long period of time may also be used.

The novel dye developers of this invention may be defined as 4,8-diamino-substituted 1,5-naphthoquinones,

NEL-

or nuclear substituted derivatives thereof, containing at least one substituent comprising a dihydroxyphenyl silver halide developing radical linked to the naphthoquinone nucleus through one of the designated --NH-- groups, or bonded to one of the 2, 3, 6 or 7 carbon atoms of the naphthoquinone nucleus. As will 'be more apparent hereinafter, the dihydroxyphenyl silver halide developing radical may be bonded directly to the --NH-- or nuclear carbon atom to provide the naphthoquinone dye developer or it may he linked indirectly thereto through an appropriate divalent linking group in the manner heretofore known in the dye developer art.

The novel dye developers of this invention may be wherein:

Each Ar is a benzene or naphthalene nucleus; Each Z may be nitro, chloro, alkyl, alkoxy,

hydroxy, carboxy, alkoxyalkyl or alkoxy-alkoxy, the alkyl moiety of any of the above-mentioned substituents having such a moiety containing less than five carbon atoms and most preferably containing 1-2 carbon atoms; m is a positive integer from 1-5; I

Each X is a substituent comprising a dihydroxyphenyl silver halide developing radical which may be bonded directly to a nuclear carbon atom of the Ar moiety or linked thereto through an appropriate divalent linking group to be described with more particularity hereinafter; Each n is a positive integer from 1-2; Each Y may be H, amino, phenylamino, naphthylamino, dihydroxyphenylamino, or a substituent of the formula:

wherein;

Q is a phenylamino substituent, including substituted derivatives thereof, e.g., nitrophenylamino; a substituent comprising a dihydroxyphenyl silver halide developing radical bonded directly to the phenylene moiety or linked thereto through an appropriate linking group as mentioned above in the description of the X moiety; or Q may also be a phenylazo, naphthylazo, or pyrazolonylazo substituent comprising together with the segment of the substituent, an azo dye of the benzeneazobenzene, benzeneazonaphthalene or benzeneazopyrazolon series; provided that there is at least one dihydroxyphenyl silver halide developing radical present in the molecule as either an X or Y substituent.

The dihydroxyphenyl silver halide developing substituents and the divalent linking groups referred to above may be selected from those heretofore well-known in the art.

As examples of useful dihydroxyphenyl silver halide developing substituents, mention may be made of orthodihydroxyphenyl, para-dihydroxyphenyl and nuclear-substituted derivatives thereof, e.g., chloro, methyl, phenyl, and/or methoxy-substituted derivatives thereof, particularly nuclear-substituted p-dihydroxyphenyls such as methylhydroquinonyl, p-rnethylphenylhydroquinonyl, chlorohydroquinonyl, methoxyhydroquinonyl, 2,6 dimethylhydroquinonyl, 2,6 dimethoxy-hydroquinonyl, Z-methoxyfi-methyl-hydroquinonyl, 2,3-dimethyl-hydroquinonyl, Z, 5,6-trimethyl-hydroquinonyl, etc.

As examples of useful divalent linking groups linking the dihydroxyphenyl moiety to the designated aryl moiety, mention may be made of the linking groups described and claimed in US. Pat. No. 3,288,778; aminophenalkylthio substituents such as disclosed in US. Patent No. 3,009,958; aminoalkylamino substituents such as disclosed in US. Pat. No. 3,002,997; aminophenalkyl substituents such as disclosed in US. Pat. No. 3,019,107; alkylthio substituents such as disclosed in US. Pat. No. 3,043,690; aminoalkyl substituents such as described in US. Pat. No. 3,062,884; aminophenyl substituents such as disclosed in US. Pat. No. 3,134,811; the acyl substituents disclosed in US. Pat. No. 3,142,564; the aminophenoxy substituents such as disclosed in US. Pat. No. 3,061,434; lower alkylene and the various other linking substituents disclosed in US. Pat. No. 3,255,001, etc. Where the linking substituent is alkylene or contains an alkyl or alkylene moiety, the number of carbon atoms is preferably l-4.

In a preferred embodiment, the Ar moieties each comprise a phenyl nucleus; one Y component is the other Y is hydrogen; and each m is 1 or 2.

Such novel dye developers are represented by the formula:

in more particularity elsewhere. The phenyl (1) and phenyl As examples of dye developers within the scope of this (2) nuclei which are not bonded to silver halide developing invention, mention may be made of:

functions are bonded to a group selected from among -OR, R, ROR, and H where R is a C to C aliphatic radical. Phenyl nucleus (3) when not bonded to a silver halide developing function can be bonded to such NH 0 OH groups as Q l alkyl-OH NE E as well as a dye of the azo series, such as those heretofore known in the art and further it may 'be bonded to a hy- 15 drogen atom or an alkyl group.

QM r

omom-Q-m:

0 HN- OH CHlCHf- The novel dye developers of Formula A can be prepared by several alternate methods. An N,N'-arylene substituted naphthoquinone or a derivative thereof can be reacted with an appropriate compound which contains a silver halide developing function. In some instances it may be advisable to protect the dihydroxyphenyl silver halide developing radical during the aforementioned reaction, e.g., by the use of the bis-acyloxyphenyl or bis-alkoxyphenyl analogue. The protective groups may be removed subsequently, e.g., by hydrolysis, to provide the desired dihydroxyphenyl moiety. The bond between the two reactants can be formed on the arylene group attached to the nitrogen atoms, or directly to the nucleus itself. The bond formation location will be dependent upon the nature of the directing groups upon the arylene moiety and/or upon the naphthoquinone nucleus. A process of this latter type wherein a Y substituent that contains such a developing function is added to the nucleus is illustrated by Example I.

They may also be prepared by reacting an N,N'-arylene substituted naphthoquinone or a substituted dreviative thereof with a silver halide developing compound such that the developing function is attached to the Ar moiety of Formula A as an X substituent, followed by the addition of a specific Y radical. Such a process is illustrated by Example H.

Still another method comprises reacting an N,N-arylene substituted naphthoquinone, which contains a Y substituent, with a compound that contains a silver halide developing function to bond the latter to the Y" substituent. Such a process is illustrated by Example III.

The dye developers of this invention have been found to give difiusion transfer images which exhibit improved stability to light, particularly as compared with azo dye developers. The dye developers of the preferred embodiment are distinguished by their ability to provide monochrome images which approximate neutral, i.e., black in color. These dye developers have their maximum absorption in the red portion of the spectrum, but they also exhibit substantial absorption in the blue and green portions of the spectrum; as a result, images which are grey or blue-grey, etc., may be prepared by using only a single dye developer. This color property is particularly significant when it is noted that most "greys and blacks are really mixtures of two or more dyes, and previous individual dye developers giving blue-grey images have been disazo dyes which are markedly less light stable. The dye developers of the preferred embodiment thus have special significance in the field of document duplication or other specialized photographic applications wherein it is desired to form dye images which are substantially neutral in color.

The novel dye developers of this invention have also been found to be extremely stable against the color degradation effects of light, humidity and/or heat.

Furthermore, these dye developers are not pH sensitive and are chemically stable in an aqueous alkaline processing medium.

The following examples of the preparation of dye developers within the scope of this invention are given for the purpose of illustration only.

EXAMPLE I Preparation of 2[4'-fi(2",5"-dihydroxyphenyl)ethyl} aniline-4,8-bis[4'-ethoxy]anilino-l,5naphthoquinone o NH-Q-O can 2.0 g. (0.0047 m.) of 4,8-bis [4'-ethoxy]anilino-l,5- naphthoquinone were placed in a flask fitted with a nitrogen inlet and the flask was deaerated with nitrogen. 40.0 g. (0.17 m.) of 4[,B-(2,5 dihydroxyphenyhethyllamline and 2.0 g. (0.0075 m.) of 4-[ 8-(2',5'-dihydroxyphenyl)ethyl]aniline hydrochloride were added to the flask with 30 cc. of dimethyl formamide which had been deaerated with. nitrogen. The mixture was heated under nitrogen in an oil bath (bath temperature 155:5 C.) for 2 /2 hours. The mixture was cooled and the product was precipitated into dilute hydrochloric acid. Methyl Cellosolve was used to rinse out the reaction flask. The product was collected by suction filtration, washed with dilute hydrochloric acid and then with water. The resulting solid was treated under nitrogen with 20.0 cc. of 5% sodium hydroxide which had been deaerated with nitrogen, filtered under nitrogen and the product was then precipitated into dilute hydrochloric acid. The solid was collected by suction filtration, washed well with water and dried in vacuo. The yield was 2.8 grams of a blue-black powder, M.P. l44-9 C. The molecular weight was calculated to be 655.8. The spectral analysis of this product indicated a Amaxv at 672 mu; e=l6,200 and a h at 628 m E: 12,400 in DMF.

EXAMPLE II Preparation of 2-anilino-4,8-bis[4'-B(2", "-dihydroxyphenyl)ethyl]anilino-l,5-naphthoquinone 4,8-bis [4 ;8(2",5" dihydroxyphenyhethyl] anilino-1,5-naphthoquinone (3.1 g.) 0.005 Aniline (0.5 g.) 0.005 Aniline hydrochloride (0.065 g.) 0.0005 Dimethyl formamide 10 cc.

The above were all placed in a cc. flask fitted with a N inlet and a condenser with Bunsen valve. The mixture was heated under N in an oil bath (bath temp. :5 for 6 hours. The product was precipitated into dilute HCl, filtered and washed well with water. The product was put under nitrogen into an apparatus designed to filter ofl? any insoluble solids from the alkali soluble dye developer. It was filtered and washed Well with water and dried in vacuo. The product was a blue-black powder l69.5-173 C. The spectral analysis of this product indicated a u at 626 m e=12,800 and a A at 670 Ill 4; e=16,400 in dimethyl formamide.

EXAMPLE III Preparation of 2 [7' hydroxy 8'(4"-13(2"',5"'-dihydroxyphenyl)ethyl)phenylazo 2' naphthylaminoJ-4, 8-b1s [4'-ethoxy] anilinol, S-naphtho quinone NH OH ii i I Hg H2 MW. 825.9 E

4[(B 2",5"-cliacetoxyphenyl)ethylJaniline hydrochloride (1.8 g.) was diazotized by means known in the art with 0.35 g. NaNO: and the resulting yellow solution was added dropwise to a stirred solution of 30 g. of 2-[7-hydroxy-2'-naphthylamino] 4,8-bis[4"-ethoxy]anilino-l,5- naphthoquinone in 300 cc. pyridine at about 15 C. The reaction mixture was slowly allowed to come to room temperature and stirring was continued for 2 hours. 300 cc. water was added, and the product formed a gum. It was dissolved in methyl Cellosolve and precipitated into dilute HCl. The solid was placed into an apparatus designed to filter olf any insoluble solids from the alkali soluble dye developer. The system was deaerated with nitrogen, and deaerated NaOH (20 cc., 50% aq.) was introduced and the resulting mixture was stirred for 45 minutes. The mixture was filtered, precipitated into dilute HCl, filtered, washed with water and dried in vacuo. The solid was reintroduced into the filter apparatus under nitrogen and the procedure was repeated. The product was dried to a black powder, that had a melting point of about 220 C.

An example of a photographic use of the dye developers herein disclosed, and set forth by way of illustration only is the following.

EXAMPLE IV (A) A photosensitive element was prepared by coating a gelatin subcoated film base at a speed of 10 feet per minute with a solution comprising 0.39 g. of the compound of Formula 1X, dissolved in 10 cc. of 2% partial acetalde hyde acetal of polyvinyl alcohol in methanol. After this coating dried, a green-sensitive silver iodobromide emulsion was coated on at a speed of 5 feet per minute and allowed to dry. This photosensitive element was exposed for 2 seconds and processed by spreading, between the thus exposed photosensitive element and a superposed imagereceiving element, an aqueous processing composition comprising:

Water100 cc.

The image-receiving element comprised a 2:1 mixture, by weight, of polyvinyl alcohol and poly-4-vinylpyridine on-a baryta paper support. After an imbibition period of approximately one minute, the image-receiving element was separated and contained a blue gray positive ima e having a D of 1.37 a D of 0.46.

(B) The same photosensitive element when processed in the same manner except with 0.2% 4'-methylphenylhydroquinone added to the processing composition had a D of 1.15 and a D of 0.08.

As was mentioned previously, the novel dyes of this invention exhibit increased stability against the color degradation effects of actinic radiation, humidty and/or heat.

Positive dye images prepared in the manner described in Example -IV were subjected to standard fading tests in a temperate climate and the percent of fading was noted after several dosages of radiation. The following tables illustrate the increased stability of the novel dyes of this invention.

TABLE 1 Dye developer Formula 1X 1 Langley=a unit of solar radiation equivalent to one gram calorie per square centimeter of irradiated surface.

14 The positive image utilized for these tests were processed with the developer composition of Example IV(A).

The dye developers bearing the formulae set forth were also tested for light stability in the manner described hereinbefore and the light stability data is set forth below.

The green positive images of Formulae XI and VIII and the blue positive images of Formula XII used for these tests were all processed with a composition of the nature utilized in Example IV(B).

The dye developers of this invention are also useful in integral multilayer photosensitive elements for use in multicolor diffusion transfer processes. As an example of such photosensitive elements, mention may be made of the photosensitive elements disclosed and claimed in the copending U.S. application of Edwin H. Land and Howard G. Rogers, Ser. No. 565,135, filed Feb. 13, 1956, now U.S. Pat. No. 3,345,163, issued Oct. 3, 1967, wherein at least two selectively sensitized photosensitive strata are superposed on a single support and are processed, simultaneously and without separation with a single common image-receiving element. A suitable arrangement of this type comprises a support carrying a red-sensitive silver halide emulsion stratum, a green-sensitive silver halide emulsion stratum and a blue-sensitive silver halide emulsion stratum, said emulsions having associated therewith, respectively, a cyan dye developer, a magenta dye developer and a yellow dye developer. -In one of the preferred embodiments of photosensitive elements of this type, the dye developers are disposed in separate alkali-permeable layers behind the photosensitive silver halide emulsion stratum with which' they are associated.

'Ihe photosensitive elements within the scope of the this invention may be used in roll film units which contain a plurality of photosensitive frames. The photosensitive elements of this invention are especially useful in composite roll film intended for use in a Polaroid Land Camera, or a similar camera structure such, for example, as the camera forming the subject matter of U.S. Pat. No. 2,435,717, issued to Edwin H. Land on Feb. 10, 1948. In general, such composite roll films comprise a photosensitive roll, a roll of image-receiving material and a plurality of pods containing an aqueous alkaline processing solution. The rolls and pods are so associated with each other that, upon processing, the photosensitive element may be superposed on the image-receiving element and the pods may be ruptured to spread the aqueous alkaline processing solution between the superposed elements. The nature and construction of the pods used in such units are well known to the art. See, for example, U.S. Pats. Nos. 2,543,181 and 2,634,886, issued to Edwin H. Land.

It will be noted that the liquid processing composition may contain one or more auxiliary or accelerating silver halide developing agents, such as p-methylaminophenyl (Metol); 2,4-diaminophenol (Amidol); benzylaminophenol; hydroquinone; a substituted hydroquinone such as toluhydroquinone, phenylhydroquinone, or 4-methyl- .phenylhydroquinone; or a 3-1pyrazolidone such as 1- phenyl-3-pyrazolidone. These silver halide developing agents are substantially colorless, at least in their unoxidized form. It is possible that some of the dye developer oxidized in exposed areas may be oxidized by an 15 energy transfer reaction with oxidized auxiliary developing agent.

In addition, development may be effected in the presence of an onium compound, particularly a quaternary ammonium compound, in accordance with the processes disclosed and claimed in US. Pat. No. 3,173,786 issued Mar. 16, 1965 to Milton Green and Howard G. Rogers.

The dye developers of this invention may be used also in conventional photographic processes, such as tray or tank development of conventional photosensitive films, plates or papers to obtain black and white, monochromatic or toned prints or negatives. By way of example, a developer composition suitable for such use may comprise an aqueous solution of approximately 12% of the dye developer, 1% sodium hydroxide, 2% sodium sulfite and 0.05% potassium bromide. After development is completed, any unreacted dye developer is washed out of the photosensitive element, preferably with an alkaline washing medium or other medium in which the unreacted dye developer is soluble. The expression toned" is used to designate photographic images wherein the silver is retained with the precipitated dye, whereas monochromatic is intended to designate dye images free of silver.

It should be noted that the dye developers of this medium are self-suflicient to provide the desired color image and do not depend upon coupling reactions to produce the desired color. They thus provide a complete departure from conventional photographic color processes in which the color is produced by a coupling reaction between a color former or coupler and the oxidized developing agent, as well as so-called auto-coupling processes in which color is obtained by a reaction of the oxidized developing agent with unoxidized developing agent.

It will be apparent that, by appropriate selection of the image-receiving element from among suitable known opaque and transparent materials, it is possible to obtain either a colored positive reflection print or a colored positive transparency. Likewise, the inventive concepts herein set forth are adaptable for multicolor work by the use of special photographic materials, for example, film materials of the type containing two or more photosensitized elements associated with an appropriate number of image-receiving elements and adapted to be treated with one or more liquid processing compositions, appropriate dye developers suitable to impart the desired subtractive colors being incorporated in the photosensitized elements or in the liquid processing compositions. Examples of such photographic materials are disclosed in U.S. Pat. No. 2,647,049 to Edwin H. Land.

As examples of useful image-receiving materials, mention may be made of nylon, e.g., N-methoxymethylpolyhexarnethylen'e adipamide, polyvinyl alcohol, and gelatin, particularly polyvinyl alcohol or gelatin containing a dye mordant such as poly-4-vinylpyridine. The image-receiving element also may contain a development restrainer, e.g., 1-phenyl-5-mereaptotetrazole, as disclosed in US. Pat. No. 3,265,498 issued Aug. 9, 1966 to Howard G. Rogers and Harriet W. Lutes.

The dye developers herein set forth are also useful in the formation of colored images in accordance with the photographic products and processes described and claimed in US. Pat. No. 2,968,554, issued to Edwin H. Land on Jan. 17, 1961.

The novel compounds herein disclosed are also suitable for use as dyes for textile fibers, such as nylon.

In the preceding portions of the specification, the expression color has been frequently used. This expression is intended to include the use of a plurality of colors to obtain black.

Since certain changes may be made in the above products, compositions and processes without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A photographic product comprising a support, a silver halide emulsion in a layer carried on said support and a dye developer in a layer on the same side of said support as said silver halide emulsion, said dye developer being a compound of the formula:

Z (in-l,

wherein:

each Ar is selected from the group consisting of a benzene and naphthalene nucleus; each Z is nitro, chloro, alkyl, alkoxy,

hydroxy, carboxy, alkoxyalkyl or alkoxyalkoxy, the alkyl moiety of any of the above-mentioned substituents having such a moiety containing less than five carbon atoms;

m is a positive integer from 1-5;

each X is a substitutent comprising a dihydroxyphenyl silver halide developing radical;

each n is a positive integer from 1-2;

each Y is hydrogen, amino, phenylamino, naphthylamino, dihydroxyphenylamino, or a substituent of the formula:

wherein:

Q is a substitutent selected from the group consisting of nitro, hydrogen, alkyl, a substituent comprising a dihydroxyphenyl silver halide developing radical bonded directly or through a linking group to the phenylene moiety, a phenylazo, naphthylazo, or pyrazolonylazo substituent comprising together with the segment of the ONE ill

NH (2) (a) wherein the phenyl nuclei (1), (2), (3) are each phenyl or an alkyl or halogen substituted derivative thereof, at least bonded to a member selected from the group consisting of NH -a1kyl-OH H, and alkyl.

3. A photographic product as defined in claim 1 wherein the dye developer is a compound of the formula:

IIIHQOCzHs on NH.@ CHrCH: C=H50HI1I i 4. A photographic product as defined in claim 1 wherein the dye developer is a compound of the formula:

NH-QOCaHa o ll azure-@451 1 1 i I GHzdH,

5. A photographic product as defined in claim 1 wherein the dye developer is a compound of the formula:

| H l [D no 5 Q 6. In a process of forming photographic images in color, the steps which comprise developing an exposed silver ML ide emulsion with an aqueous alkaline solution of a dye developer compound having the formula:

each Ar is selected from the group consisting of a benzene and naphthalene nucleus; each Z is nitro, chloro, alkyl, alkoxy,

hydroxy, carboxy, alkoxyalkyl or alkoxyalkoxy, the alkyl moiety of any of the above-mentioned substituents having such a moiety containing less than five carbon atoms;

In is a positive integer from 1-5;

each X is a substituent comprising a dihydroxyphenyl silver halide developing radical;

' each n is a positive integer from 1-2;

each Y is hydrogen, amino, phenylamino, naphthylamino, dihydroxyphenylamino, or a substituent of the formula:

wherein:

Q is a substituent selected from the group consisting of nitro, hydrogen, alkyl, a substituent comprising a dihydroxyphenyl silver halide developing radical bonded directly or through a linking group to the phenylene moiety, a phenylazo, naphthylazo, or pyrazolonylazo substituent comprising together with the segment of the substituent, an azo dye of the benzeneazobenzene, benzeneazonaphthalene or I benzeneazopyrazolone series; provided that there is at least one dihydroxyphenyl silver halide developingradical present in the molecule as either an X or Y substituent, oxidizing said dye developer as a function of the point-to-point degree of development, forming in undeveloped areas of said silver halide emulsion an imagewise distribution of unoxidized dye developer and transferring at least part of said imagewise distribution of unoxidized dye developer, by imbibition, from said emulsion to an image-receiving layer in superposed relationship with said emulsion to impart a dye transfer image to said image-receiving layer.

19 7. In a process of forming photographic images in color, the steps which comprise developing an exposed silver ha lide emulsion with an aqueous alkaline solution of a dye developer compound having the formula:

NH -o 02115 oxidizing said dye developer as a function of the point-topoint degree of development, forming in undeveloped areas of said silver halide emulsion an imagewise distribution of unoxidized dye developer and transferring at least part of said imagewise distribution of unoxidized dye developer, by imhibition, from said emulsion to an imagereceiving layer in superposed relationship with said emuliion to impart a dye transfer image to said image-receiving ayer.

8. The process as defined in claim 6, wherein said dye developer is dispersed prior to exposure in a photosensitive element comprising said silver halide emulsion, and including the step of permeating said photosensitive element with an aqueous alkaline liquid capable of solubilizing said dye developer.

9. The process as defined in claim 8, wherein said liquid is introduced by being spread in a substantially uniform layer between said photosensitive element and an image receiving element comprising said image-receiving layer as said elements are brought into superposed relationship.

10. The process as defined in claim 9, wherein said liquid contains a thickener for increasing viscosity and for facilitating the spreading thereof between said photosensitive element and said image-receiving element.

11. The process as defined in claim 6, wherein said dye developer is dissolved in an aqueous alkaline solution prior to application of said solution to said exposed emulsion.

References Cited UNITED STATES PATENTS 2,623,872 12/1952 Kartaschotf et al. .i- 260-396 2,764,600 9/1956 Merian 260-396 2,983,606 5/1961 Rogers 96-77 3,209,016 9/1965 Blout 96-29 3,249,435 5/1966 Rogers 96-77 3,297,441 1/1967 Green et al 96-77 3,338,659 8/1967 Bosshard et a1. 260-396 I. TRAVIS BROWN, Primary Examiner I. L. GOODROW, Assistant Examiner US. Cl. X.R. 96-3, 77 

